Load break connectors are well-known in the high voltage electrical distribution art. As presently constituted these connectors generally include a removable terminator and a stationary bushing. It is to an improvement in bushing construction that the present invention is directed.
In such connectors as generally known, the terminator comprises a tubular body of insulating material (usually elastomeric) within a semiconductive outer shell. The insulating body has a longitudinal bore within which is disposed the axial connector electrode, the electrode being spaced from the bore walls of the terminator a distance sufficient to receive and mate with the tubular bushing body.
The receiving bushing assembly comprises a tubular insulating body (usually elastomeric) with an outer conductive or semi-conductive shell. Within the bore for most of its axial length is a metallic conductive thin-walled tube, usually copper. At one end, the conductive tube has secured therein a suitable member adapted to connect to a transformer bushing or the like.
At its other end, the terminator mating end, the metallic tube is inserted within the bore of the body. The open mouth of the conductive tube is threaded, the threaded end terminating and being recessed a distance within the bushing body. Either within the threaded section or further within the conductive tube, a tubular connector insert sleeve of metallic material is fitted. This insert sleeve may be split or otherwise configured to receive and grasp the terminator electrode in a tight-fitting conductive relationship.
In the mouth of the bushing is inserted an arc snuffing insert. The insert is tubular and is configured to fit tightly in the bushing assembly mouth. The cylindrical outside wall of the insert is threaded at one end to mate with the threaded conductor tube and hold the insert in place.
The insert is molded or otherwise suitably fabricated of a plastic material known to aid in extinguishing an arc due to the inherent properties of the material. One family of such materials is known as polyoxymethylene of the type known by the trademark Delrin. Other known materials may be used for this purpose.
As is known, such materials tend to extinguish an arc drawn between an electrode being extracted from the bushing and the tubular sleeve conductor end.
In extinguishing the arc, the material of the insert generates gases when subjected to the heat of an arc. The gas generated has a deionizing effect on the gases and acts to confine and extinguish the arc. The type of extinguishing tubes known in the art have the internal bore wall as the surface contacted by the arc in generating gases.